96 GT Ford Racing / SVO project

[white95]

(2003 Cobra bypass valve on SVO blower)

The boost bypass needs to reference air from before and after the blower. One line goes to the intake and needs to see boost. The other needs to be in front of the throttle body, in the cold air intake or simply open to atmosphere. Once you have that sorted you need to verify if it is functional? If it isn’t you will have a no boost condition without lots of throttle and then it’ll “come on” abruptly. It’ll also have sketchy low speed manners and get terrible fuel mileage. It’s easy to check, have someone start the car and watch the arm on the bypass. Start the car and the arm should open the valve, blip the throttle and it should close the valve.

If that doesn’t happen, it is possible you have a vacuum leak. You should hook up a vacuum gauge and see what she’s pulling at idle. This one was about $28-$29 at Oreillys Auto Parts. I don’t know about your specific bypass valve but the unit on my M122 needs 18 inches of mercury (in Hg) to open. Anything lower than that and it simply won’t open unless you’re really on the throttle. It would cruise around on 1# of boost. Sound familiar yet?

Do you have aftermarket cams? If so, they’ll add to the problem.

 

[Burninriverdiver]

I have 48 lb and my tuner told me they are too much. Funny that is what holley recommended but I am sure they are thinking to leave room to grow later.

My tuner also told me to get rid of my pcv valve. I have got mixed reactions on what to do with it before this but I trust him more then most and will be doing so.

I would think that you should take the charcoal can out of the vac lines but I am still learning as well.

My tuner said if these don't work right to go up in a size with quality parts, I think his biggest doubt with running these was that the cheaper parts don't seem to be able to be adjusted down at idle very well.

I left the charcoal can alone so far, if it gets running fine with it I'll probably leave it alone.

 

[Burninriverdiver]

So you have the green tops? What maf are you running?


Sent from my iPhone using Tapatalk

I believe it's a 90mm maf, I just ordered one compatible with an f-150 lightning to keep it somewhat relative

 

[Burninriverdiver]

View attachment 1908 (2003 Cobra bypass valve on SVO blower)

The boost bypass needs to reference air from before and after the blower. One line goes to the intake and needs to see boost. The other needs to be in front of the throttle body, in the cold air intake or simply open to atmosphere. Once you have that sorted you need to verify if it is functional? If it isn’t you will have a no boost condition without lots of throttle and then it’ll “come on” abruptly. It’ll also have sketchy low speed manners and get terrible fuel mileage. It’s easy to check, have someone start the car and watch the arm on the bypass. Start the car and the arm should open the valve, blip the throttle and it should close the valve.

If that doesn’t happen, it is possible you have a vacuum leak. You should hook up a vacuum gauge and see what she’s pulling at idle. This one was about $28-$29 at Oreillys Auto Parts. I don’t know about your specific bypass valve but the unit on my M122 needs 18 inches of mercury (in Hg) to open. Anything lower than that and it simply won’t open unless you’re really on the throttle. It would cruise around on 1# of boost. Sound familiar yet?

Do you have aftermarket cams? If so, they’ll add to the problem.

View attachment 1907

Thanks! You may have just given me the information I needed. I never thought about it but my bypass only has one outlet on it and I put a hose over it and connected it to the outlet on top of the manifold; the car seems to run better when it isn't hooked up at all. It is nearly impossible to get the valve to close back up and make boost (especially when it isn't moving) the way it's hooked up now.

I need to test it out but the older style may just need to be vented to the atmosphere, otherwise I could look into replacing it with one off of a cobra.

 

[Burninriverdiver]

Cleaned up, changed the end caps, and knocked off the rust on the free set of Ford Racing 30lb injectors I got with the supercharger. I plan to swap these in before I spend another $350 on new injectors with adaptors to clear up the misfire. Hope it works

 

[PinkieT]

I am SOOOOOO glad you bought the supercharger instead of me. I would have given up long ago.

 

[ttocs]

View attachment 1918 Cleaned up, changed the end caps, and knocked off the rust on the free set of Ford Racing 30lb injectors I got with the supercharger. I plan to swap these in before I spend another $350 on new injectors with adaptors to clear up the misfire. Hope it works

You can send them off and have them cleaned and calibrated for less

 

[Burninriverdiver]

I am SOOOOOO glad you bought the supercharger instead of me. I would have given up long ago.

Haha yeah I contemplated putting it back to stock a few times but I have a feeling I'd do that and still have a misfire! I'll keep plugging along and it'll be running eventually, just glad I have the luxury of not depending on it for transportation

 

[Burninriverdiver]

You can send them off and have them cleaned and calibrated for less

You've got a good point! I may do that but I'm too impatient right now and want to plug them in to see what happens. If it's running horribly I'll shut it down and consider that option along with new injectors

 

[ttocs]

an easy way to see if the injectors are or are not firing is to check the temp of the individual header pipes with an infrared temp gun to find the cooler cylinders.

 

[Burninriverdiver]

an easy way to see if the injectors are or are not firing is to check the temp of the individual header pipes with an infrared temp gun to find the cooler cylinders.

I need to figure out if I can see the exhaust manifolds from under the car, unfortunately they aren't very visible from the top side on these bulky 4.6 motors

 

[96blak54]

^ so true

You should see it with a 5.4l! It aint happenen

 

[Frank.JD.Perez]

The injectors are brand new from China (I assume) off eBay; I think it would be better to send my memory off to be cleaned! I seem to forget that you can't have a quality & inexpensive part unless you spend a lot of time making it yourself.

well theres your problem lol. bad/faulty injectors can cause crazy things to be read by the computer. i remember when i bought some 30lbs off a guy... my tuner and i were trying to get the mapping right, but the injectors just werent flowing right. my tuner made it say the injectors were flowing something like 100 and the car still wasn't cooperating. we swapped back to the 24lbs and it was night and day. we wasted probably an hour on that issue.

 

[Burninriverdiver]

well theres your problem lol. bad/faulty injectors can cause crazy things to be read by the computer. i remember when i bought some 30lbs off a guy... my tuner and i were trying to get the mapping right, but the injectors just werent flowing right. my tuner made it say the injectors were flowing something like 100 and the car still wasn't cooperating. we swapped back to the 24lbs and it was night and day. we wasted probably an hour on that issue.

Yeah I pretty much assume they are garbage. Last night I swapped in the set of ford 30lb injectors I got for free to test that out, its misfiring still and the AFR jumped significantly so i shut it down for the night so my neighbors didn't have to listen to my obnoxious car. I need to check all my spark plug wires again to make sure they're seated properly (I unplugged them, covered the holes, and put a towel down to soak up the fuel)

 

[ttocs]

is the new maf calibrated for, or is the tune going to be changed for the larger injectors?

 

[Burninriverdiver]

is the new maf calibrated for, or is the tune going to be changed for the larger injectors?

I think the tuner will send another file if I buy the injectors from him, if not I'll be sending more cash.

Did some messing around a little bit today and I can't get the car running right with the 30lb ford injectors either. I'm contemplating putting the stock tune, injectors, and MAF sensor back in to see if I can at least get it to run normal before I keep chasing down my issue with too many variables. I don't know yet though

 

[Burninriverdiver]

Swapped back to my stock (properly working) injectors, MAF sensor and returned the tune back to stock tonight.

Still misfiring. It's got to be a wiring or vacuum issue. I plan to keep chasing down the problem but at this point I am tempted to part it out or kick every body panel in on it (don't worry I won't do the latter)

 

[evilcw311]

Don’t get frustrated and don’t part it out. It’s probably something small that your simply overlooking. Times like this it’s best to just walk away for a few days and just not worry about it.

Then when you come back with a clear mind you’ll probably find the issue.


Sent from my iPhone using Tapatalk

 

[Burninriverdiver]

Don’t get frustrated and don’t part it out. It’s probably something small that your simply overlooking. Times like this it’s best to just walk away for a few days and just not worry about it.

Then when you come back with a clear mind you’ll probably find the issue.


Sent from my iPhone using Tapatalk

You're probably right! I stepped back and looked at a bunch of Mach 1s and green Bullitt mustangs for sale online (I always wanted a bullitt) the last few days to think about the cost of a new platform. It doesn't make sense to ditch this at all so I'll keep plugging along.

Edit: after unsheathing some of the wires I soldered I made an incredibly stupid discovery. I connected the red/green wire to the red/blue wire and vice versa running to the coil pack. That's a huge issue.... hope it's my only culprit

 

[Burninriverdiver]

Well I fixed the two wires that were mixed up and plugged everything back in leaving all the wires exposed in case I need to keep chasing issues.

I fired it up and it starts much easier but it still has a noticeable miss. I plan to dissect the drivers side portion of the wiring harness next and see what else I screwed up